1. Technical Field
The present invention relates to a backlight device of an edge light type which illuminates a display panel on which an image is displayed, and to a display apparatus.
2. Description of Related Art
A display apparatus which displays an image on the front surface thereof using a non-luminescent display panel such as a liquid-crystal panel includes a backlight device illuminating the display panel from the rear side. An example of the backlight device includes an edge light type in which a light guide plate is located on the rear side of the display panel while a light source is arranged to be opposed to an end face of the light guide plate. In a backlight device of the edge light type, light from the light source enters an end face of the light guide plate, travels inside the light guide plate, and is emitted from one flat surface of the light guide plate. For the light source, a light emitting diode (LED) is used, for example. International Patent Publication No. WO2008/090646 describes a backlight device of the edge light type.
A light guide plate may shift its position in the thickness direction due to a warp or the like caused by expansion/contraction in accordance a change in an environment such as temperature, moisture or the like. When the positional shift of the light guide plate occurs, the position of an end face of the light guide plate is somewhat shifted from the light path which is so defined as to make the light from a light source enter the end face of the light guide plate, thereby reducing the amount of light entering the end face of the light guide plate, reducing the amount of light for illuminating the display panel, and thus darkening the image display screen. Moreover, light leakage, i.e. light leaking from the end face without entering the light guide plate, causes unevenness in luminance in the display screen, which degrades the displaying quality of an image. Thus, the light guide plate is sandwiched and held between a support member disposed on the rear side and a pressing member for pressing the light guide plate from the front side, thereby suppressing the positional shift of the light guide plate.